OK, I won't put this in the serious ship naming thread. It's been pointed out that naming a ship after a capital or country being sunk would cause damage to national morale and deliver a propaganda coup to the enemy. Therefore, how about naming the more expendable vessels after things we hate, so then morale won't be hurt. Also, despite the saying 'I wouldn't wish it on my worst enemy,' there are many irritations that we would wish on our worst enemies. Sure, you can use then names of enemy leaders, but that might be confusing for intel and really not that relatable.
So, for example:
'In a much-derserved offensive, HMS Halitosis is spearheading an attack on our worst enemies.'
'We have received news that HMS Those Bastards From Accounts, Especially Jeremy has been sunk. No lives that anyone cares about were lost - they had it coming to them.'
Win either way!